APOD: 2021 July 23 - Elephant, Bat, and Squid Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 23 Elephant, Bat, and Squid Image Credit &Copyright: Patrick Hsieh Explanation: Sprawling emission nebulae IC 1396 and Sh2-129 mixglowing interstellar gas and dark dust clouds inthis 10 degree wide fieldof view toward the northern constellationCepheus the King.Energized by its bluish central star IC 1396 (left)is hundreds of light-years across and some 3,000 light-years distant.The nebula's intriguing dark shapes includea winding dark cloud popularly known as theElephant's Trunk below and right of center.Tens of light-years long, it holds the rawraw material for star formation and is known to hideprotostarswithin.Located a similar distance from planet Earth, thebright knots and swept back ridges of emission of Sh2-129 on the rightsuggest its popular name, theFlying Bat Nebula.Within the Flying Bat, the most recently recognizedaddition to this royal cosmic zoo is the faint bluish emission from Ou4, theGiant Squid nebula. Tomorrow's picture: at the edge of space<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights...

APOD: 2021 July 22 - NGC 7814: Little Sombrero with Supernova Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 22 NGC 7814: Little Sombrero with Supernova Image Credit &Copyright: CHART32 Team Explanation: Point your telescope toward the high flying constellationPegasusand you can find thisexpanseof Milky Way stars and distant galaxies.NGC 7814 is centered in the prettyfield of view that would almostbe covered by a full moon.NGC 7814 issometimes called the Little Sombrero for itsresemblance to the brighter more famous M104,the Sombrero Galaxy.Both Sombrero and Little Sombrero are spiral galaxiesseen edge-on, and both haveextensive halosand centralbulges cut by a thin disk with thinner dust lanes in silhouette.In fact, NGC 7814is some 40 million light-years away and an estimated 60,000 light-yearsacross.That actually makes theLittle Sombreroabout the same physical size asits better known namesake, appearing smaller and fainteronly because it is farther away.In this telescopic view from July 17, NGC 7814 is hosting a newlydiscovered supernova, dominant immediately to the left of the galaxy's core.Cataloged as SN 2021rhu,the stellar explosion has been identified as aType Iasupernova, useful toward calibrating thedistance scaleofthe universe. Tomorrow's picture: cosmic zoo<|...

APOD: 2021 July 21 - Colors: Ring Nebula versus Stars Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 21 Colors: Ring Nebula versus Stars Image Credit: Robert Vanderbei(Princeton U.) Explanation: What if you could see, separately, all thecolors of the Ring?And of the surrounding stars?There's technology for that.The featured image shows the Ring Nebula (M57) and nearby stars through such technology: in this case, a prism-like diffraction grating. The Ring Nebula is seen only a few times because it emits light, primarily, in only a few colors.The two brightest emitted colors are hydrogen (red) and oxygen (blue), appearing as nearly overlapping images to the left of the image center. The image just to the right of center is the color-combined icon normally seen. Stars, on the other hand, emit most of their light in colors all across the visible spectrum. These colors, combined, make a nearly continuous streak -- which is why stars appear accompanied by multicolored bars. Breaking object light up into colors is scientifically useful because it can reveal the elements that compose that object, how fast that object is moving,...

APOD: 2021 July 20 - Thors Helmet Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 20 Thor's Helmet Image Credit & Copyright: Bernard Miller Explanation: Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages.Heroically sized even for aNorse god,Thor's Helmet is about 30 light-years across.In fact, the cosmic head-covering is more likean interstellar bubble, blown with a fastwind from the bright, massive star near the bubble's center.Known as aWolf-Rayet star, the central star is an extremely hot giant thought to be in a brief,pre-supernova stage of evolution.NGC 2359 is located about15,000 light-years away toward the constellation of the Great Overdog.This remarkably sharp imageis a mixed cocktail of data from broadband and narrowband filters,capturing not only natural looking stars but details ofthe nebula'sfilamentary structures.The star in the center of Thor's Helmet is expected to explode in a spectacularsupernova sometime within the next few thousand years. Almost Hyperspace: Random APOD Generator Tomorrow's picture: colors of ring <| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD|...

APOD: 2021 July 19 - Framed by Trees: A Window to the Galaxy Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 19 Framed by Trees: A Window to the Galaxy Image Credit & Copyright: Will Godward Explanation: The photographer had this shot in mind for some time.He knew that objects overhead are the brightest -- since their light is scattered the least by atmospheric air.He also that knew the core of our Milky Way Galaxy was just about straight up near midnight around this time of year in South Australia. Chasing his mental picture, he ventured deep inside the Kuipto Forest where tall radiata pines blocked out much of the sky -- but not in this clearing. There, through a window framed by trees, he captured his envisioned combination of local and distant nature.Sixteen exposures of both trees and the Milky Way Galaxy were recorded.Antares is the bright orange star to left of our Galaxy's central plane, while Alpha Centauri is the bright star just to the right of the image center. The direction toward our Galaxy's center is below Antares. Although in...

APOD: 2021 July 18 - The Andromeda Galaxy in Ultraviolet Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 18 The Andromeda Galaxy in Ultraviolet Image Credit: NASA, JPL-Caltech, GALEX Explanation: What does the Andromeda galaxy look like in ultraviolet light?Young blue stars circling the galactic center dominate. A mere 2.5 million light-years away, the Andromeda Galaxy, alsoknown as M31, really is just next door as large galaxies go.Spanningabout 230,000 light-years, it took 11 different image fields from NASA's Galaxy Evolution Explorer (GALEX) satellitetelescope to produce this gorgeous portrait of the spiral galaxy inultraviolet light in 2003.While its spiral arms stand out invisible light images,Andromeda's arms look more like rings in ultraviolet.The rings are sites of intense star formation and have been interpreted asevidence that Andromeda collided with its smaller neighboring elliptical galaxy M32 more than 200 million years ago.The Andromeda galaxy and our own comparable Milky Way galaxy are the most massive members of theLocal Groupof galaxies and are projected to collide in several billion years -- perhaps around the time that our Sun's atmosphere will expand to engulf the Earth. Tomorrow's picture:...

APOD: 2021 July 17 - Alphonsus and Arzachel Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 17 Alphonsus and Arzachel Image Credit &Copyright: Noel Donnard Explanation: Point your telescopeat tonight's first quarter Moon.Along the terminator,the shadow line between night and day,you might find these two large cratersstaring back at you withan owlish gaze.Alphonsus(left) andArzachelare ancient impact craters onthe north eastern shores of Mare Nubium, the lunar Sea of Clouds.The larger Alphonsus is over 100 kilometers in diameter.A low sun angle highlights the crater'ssharp 1.5 kilometer high centralpeak in bright sunlight and dark shadow.Scouting for potential Apollo moon landing sites, theRanger 9 spacecraftreturned closeup pictures of Alphonsus beforeit crashed in the crater just northeast (toward the upper left)of its central mountain in 1965.Alpetragius,between Alphonsus and Arzachel,is the small crater with the deeply shadowed floor andoverly large central beak. Tomorrow's picture: 2.5 million light-years away<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA /GSFC& Michigan Tech. U.

APOD: 2021 July 16 - Love and War by Moonlight Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 16 Love and War by Moonlight Image Credit &Copyright: Shi Huan Explanation: Venus,named for the Roman goddess of love, andMars,the war god's namesake, come togetherby moonlightin this serene skyview, recorded on July 11from Lualaba province, Democratic Republic of Congo, planet Earth.Taken in the western twilight sky shortly after sunsetthe exposure also recordsearthshine illuminating the otherwisedark surface of theyoung crescent Moon.Of course the Moon has moved on.Venus still shines in the west though as theeveningstar, third brightest object in Earth's sky,after the Sun and the Moon itself.Seen here above a brilliant Venus,Mars moved even closerto the brighter planet and by July 13 could be seen onlyabout a Moon's width away.Mars has since slowly wandered away from much brighter Venus in thetwilight, but both are sliding toward bright star Regulus.Alpha star of the constellation Leo, Regulus lies off thetop of this frame and anticipates avisit from Venusand then Mars in twilight skies ofthe coming days. Tomorrow's picture: when the moon watches you<| Archive| Submissions | Index| Search|...

APOD: 2021 July 15 - The Dark Tower in Scorpius Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 15 The Dark Tower in Scorpius Image Credit &Copyright:Data - Martin Pugh,Processing - Rocco Sung Explanation: In silhouette against a crowded star fieldalong the tail of the arachnalogical constellationScorpius,this dusty cosmic cloud evokes for some the image of anominousdark tower.In fact, clumps of dust and molecular gascollapsingto form stars may well lurk within the dark nebula,a structure that spans almost 40 light-years across thisgorgeous telescopic portrait.Known as acometary globule, the swept-back cloud,is shaped by intense ultraviolet radiation fromthe OB association of veryhot stars in NGC 6231,off the upper edge of the scene.That energetic ultraviolet light also powers the globule's borderingreddish glow of hydrogen gas.Hot stars embedded in the dustcan be seen as bluishreflection nebulae.This dark tower, NGC 6231, andassociated nebulae are about 5,000 light-years away. Tomorrow's picture: love and war by moonlight<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy Policy and Important NoticesA service of:ASD atNASA...

APOD: 2021 July 14 - GW200115: Simulation of a Black Hole Merging with a Neutron Star Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. GW200115: Simulation of a Black Hole Merging with a Neutron Star Video Credit: Simulation: S.V. Chaurasia (Stockholm U.), T. Dietrich (Potsdam U. & MPIGP); Visualization: T. Dietrich (Potsdam U. & MPIGP),N. Fischer, S. Ossokine, H. Pfeiffer (MPIGP) Explanation: What happens when a black hole destroys a neutron star?Analyses indicate that just such an event created gravitational wave event GW200115, detected in 2020 January by LIGO and Virgo observatories.To better understand the unusual event, the featured visualization was created from a computer simulation.The visualization video starts with the black hole (about 6 times the Sun's mass) and neutron star (about 1.5 times the Sun's mass) circling each other, together emitting an increasing amount of gravitational radiation.The picturesque pattern of gravitational wave emission is shown in blue.The duo spiral together increasingly fast until the neutron star becomes completely absorbed by the black hole. Since the neutron star did not break apart during the collision, little light escaped -- which matches the lack of...

APOD: 2021 July 13 - Saturns Iapetus: Painted Moon in 3D Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 13 Saturn's Iapetus: Painted Moon in 3D Image Credit: NASA,ESA,JPL,SSI,Cassini Imaging Team; 3D Rendering: NASA's VTAD Explanation: What has happened to Saturn's moon Iapetus? Vast sections ofthis strange world are dark brown, while others are as bright white. The composition of the dark material is unknown, butinfrared spectra indicate that it possibly contains some dark form ofcarbon.Iapetus also has an unusualequatorial ridgethat makes it appear like a walnut. To help better understand this seemingly painted moon,NASA directed therobotic Cassini spacecraft orbiting Saturn to swoopwithin 2,000 kilometers in 2007.Iapetus is pictured here in 3D. A huge impact crater seen in the south spans a tremendous 450 kilometersand appears superposed on anolder crater of similar size.The dark materialis seen increasingly coating the easternmost part ofIapetus, darkening craters and highlands alike. Close inspection indicates that the dark coating typically faces the moon's equator and is less than a meter thick.A leading hypothesis is that the dark material is mostlydirt leftover when relatively warm but dirty icesublimates.An initial...

APOD: 2021 July 12 - M27: The Dumbbell Nebula Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 12 M27: The Dumbbell Nebula Image Credit & Copyright: Bray Falls & Keith Quattrocchi Explanation: What will become of our Sun?The first hint of our Sun's future was discovered inadvertently in1764.At that time,Charles Messier was compiling a listof diffuse objects not to be confused with comets.The 27th object onMessier's list, now known asM27 or the Dumbbell Nebula, is aplanetary nebula,one of the brightestplanetary nebulae on the sky -- and visibletoward the constellation of the Fox (Vulpecula) with binoculars.It takes light about 1000 years to reach us from M27, featured here in colors emitted byhydrogen andoxygen.We now know that in about 6 billion years, our Sun will shed its outer gases into a planetary nebula like M27, while its remaining center will become an X-ray hot white dwarf star. Understanding the physics and significance ofM27was well beyond 18th century science, though.Even today, many things remain mysterious aboutplanetary nebulas, including how their intricate shapes are created. Tomorrow's picture: Iapetus 3D <| Archive| Submissions | Index| Search| Calendar| RSS|...

APOD: 2021 July 11 - Find the Moon Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 11 Find the Moon Image Credit & Copyright: Jimmy Westlake(Colorado Mountain College) Explanation: Where's the Moon?Somewhere in this image, the Earth's Moon is hiding. The entire Moon is visible, in its completely full phase, in plain sight.Even the photographer's keen eye couldn't find it even though he knew exactly where to look -- only thelong exposure of his camera picked it up -- barely. Although by now you might be congratulating yourself on finding it, why was it so difficult to see?For one reason, this photograph was taken during atotal lunar eclipse, when the Earth's shadow made the Moon much dimmer than a normal full Moon.For another, the image, taken inColorado,USA,was captured just before sunrise.With the Moon on the exact opposite side of the sky from the Sun, this meant that the Sun was just below the horizon, but stillslightly illuminatingthe sky.Last, as theMoon was only about two degrees above the horizon, thelarge volume of air between the camera and the horizon scattered a lot of light...

APOD: 2021 July 10 - Mercury and the Da Vinci Glow Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 10 Mercury and the Da Vinci Glow Image Credit &Copyright:Gabriel Funes Explanation: On July 8th early morning risers saw Mercury near an old Moonlow on the eastern horizon.On that datebright planet, faint glow of lunar night side, and sunlit crescentwere captured in this predawn skyscape from Tenerife'sTeide National Park in the Canary Islands. Never far from the Sun in planet Earth's sky, thefleeting inner planetshines near its brightest in the morning twilight scene.Mercury lies just below the zeta star of the constellation Taurus,Zeta Tauri,near thetipof the celestial bull's horn.Of course the Moon's ashen glow is earthshine, earthlight reflectedfrom the Moon's night side.A description of earthshine, in terms of sunlightreflected by Earth's oceans illuminatingthe Moon's dark surface, was written over 500 years ago byLeonardo da Vinci.Waiting for the coming dawn in the foreground are theTeide Observatory'ssentinels of the Sun, also known as (large domes left to right) theTHEMIS,VTT, and GREGOR solar telescopes. Tomorrow's picture: try to see the Moon<| Archive| Submissions | Index| Search| Calendar|...

APOD: 2021 July 9 - M82: Starburst Galaxy with a Superwind Discover the cosmos!Each day a different image or photograph of our fascinating universe isfeatured, along with a brief explanation written by a professional astronomer. 2021 July 9 M82: Starburst Galaxy with a Superwind Image Credit &Copyright:Team ARO,Alentejo Remote Observatory Explanation: M82 is a starburst galaxywith a superwind.In fact,through ensuing supernova explosions andpowerful winds from massive stars,the burst of star formation in M82is driving a prodigious outflow.Evidence for the superwindfrom the galaxy's central regionsis clear in sharp telescopic snapshot.The composite image highlights emission fromlong outflow filaments of atomic hydrogen gas in reddish hues.Some of the gas in the superwind,enriched in heavy elementsforged in the massive stars,will eventually escape intointergalactic space.Triggered by aclose encounter withnearby large galaxy M81,the furious burst of star formation in M82 should last about100 million years or so.Also known as the Cigar Galaxy for its elongated visual appearance,M82 is about 30,000 light-years across.It lies 12 million light-years away near the northern boundary ofUrsa Major. Tomorrow's picture: Mercury and the Da Vinci Glow<| Archive| Submissions | Index| Search| Calendar| RSS| Education| About APOD| Discuss| > Authors & editors: Robert Nemiroff(MTU) &Jerry Bonnell (UMCP)NASA Official: Phillip NewmanSpecific rights apply.NASA WebPrivacy...